The Pentagon has requested $220.3 million in 2014 to bolster Israel's "Iron Dome" missile defense system despite broader cuts to US military spending, according to budget documents.
The US Missile Defense Agency also is asking for an additional $175.9 million in fiscal year 2015 for Israel's homegrown missile defense network, according to the agency's budget proposal posted online.
The Pentagon already invested $204 million on the system in 2011 and $70 million in 2012.
Defense Secretary Chuck Hagel promised in talks in March with his Israeli counterpart, Ehud Barak, who has since retired, that Washington would continue to fund anti-missile weaponry, including Iron Dome, despite fiscal pressures.
The budget details emerged before Hagel's planned visit to Israel next week, his first as defense secretary.
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The Republican majority in the House of Representatives in May 2012 called for additional funding of roughly $680 million for the Iron Dome program.
US military assistance to Israel comes to about three billion dollars a year to ensure the country's "qualitative military edge" in the region, as mandated by Congress.
For its part, Israel has spent a billion dollars on the development and production of Iron Dome batteries.
Israeli officials say the Iron Dome program proved a success in battle last year.
In eight days of fighting between Israel and Palestinian militants in November, the Israeli military said it brought down 421 of 1,354 rockets fired from the Gaza Strip.
Of those which landed, 58 hit urban areas while the rest fell in open fields, causing no damage.